Author Affiliations
Abstract
1 Key Laboratory of Advanced Transducers and Intelligent Control System, Ministry of Education, Taiyuan 030024, China
2 College of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024, China
3 School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, China
4 Guangdong Provincial Key Laboratory of Photonics Information Technology, Guangzhou 510006, China
5 Center for Information Photonics & Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 610031, China
Optical chaos communication and key distribution have been extensively demonstrated with high-speed advantage but only within the metropolitan-area network range of which the transmission distance is restricted to around 300 km. For secure-transmission requirement of the backbone fiber link, the critical threshold is to realize long-reach chaos synchronization. Here, we propose and demonstrate a scheme of long-reach chaos synchronization using fiber relay transmission with hybrid amplification of an erbium-doped fiber amplifier (EDFA) and a distributed fiber Raman amplifier (DFRA). Experiments and simulations show that the hybrid amplification extends the chaos-fidelity transmission distance thanks to that the low-noise DFRA suppresses the amplified spontaneous emission noise and self-phase modulation. Optimizations of the hybrid-relay conditions are studied, including launching power, gain ratio of DFRA to EDFA, single-span fiber length, and number of fiber span. A 1040-km chaos synchronization with a synchronization coefficient beyond 0.90 is experimentally achieved, which underlies the backbone network-oriented optical chaos communication and key distribution.
Photonics Research
2023, 11(6): 953
1 西南交通大学信息科学与技术学院，四川 成都 611756
2 上海交通大学区域光纤通信网与新型光通信系统国家重点实验室，上海 200240
提出并实验验证了一种基于硅基片上光路由的大规模光载一体化接收机多天线全球导航卫星信号（GNSS）差分定位系统。该系统基于光载无线（RoF）分布式天线架构实现远端多点GNSS信号采集，并利用低损耗、大带宽、抗电磁干扰的RoF传输链路实现远端采集GNSS信号的本地端集中式接收。在本地端处，利用互补金属氧化物半导体（CMOS）工艺兼容的高速硅基光开关芯片实现不同监测节点光载GNSS信号的定时切换与差分解算，构建基于片上光路由的时分复用型一体化接收机多天线GNSS定位系统。在实验中，利用自主研制的1×8马赫-曾德尔干涉型热光硅基光开关芯片构建了具有5个远端监测节点的多天线GNSS定位实验系统，GNSS信号的RoF传输距离为10 km。实验结果表明，该光开关芯片模块的实时响应时间小于200 μs，可在无需额外光放大的条件下稳定支撑10 km外5个远端监测节点的高精度定位，其在东（E）、北（N）、高（U）方向的定位精度均达到毫米量级。
光电子学 微波光子学 硅基光开关芯片 全球导航卫星系统 一体化接收机多天线 高精度定位 光学学报
2022, 42(24): 2425001
西南交通大学信息光子与通信研究中心，四川 成都 611756
针对光纤传输系统中多重物理损伤效应严重影响传输性能的情况，为保障高速光传输网络的正常运行，对传输信号进行光性能监测是必不可少的。提出一种基于卷积神经网络（CNN）的多任务光性能监测研究方案，将强度轮廓与强度波动特征作为CNN模型输入，对传输信号调制格式与光信噪比（OSNR）进行联合监测。研究结果表明，所有调制格式（28-GBaud PDM-QPSK/-8QAM/-16QAM/-32QAM/-64QAM）均可在20% 前向纠错（FEC）阈值条件（误码率为2.4×10-2）所对应的OSNR下实现100%的识别精度。此外，当强度轮廓特征、强度波动特征和两种特征联合作为神经网络模型输入时，OSNR监测的平均绝对误差分别为0.282 dB、0.245 dB、0.165 dB，均方根误差分别为0.352 dB、0.311 dB、0.218 dB。随后，进一步研究了残余色散度对所提方案监测性能的影响。
光通信 调制格式识别 光信噪比监测 卷积神经网络 偏振解复用 光学学报
2022, 42(22): 2206002
西南交通大学信息光子与通信研究中心，四川 成都 611756
针对跨洋光纤通信系统中存在严重的噪声累积和非线性效应等问题，将概率整形（PS）技术与子载波复用（SCM）技术相结合以缓解跨洋传输链路损伤，进而实现系统传输性能的提升。通过在商用VPI软件中搭建跨洋光纤传输仿真链路，对单载波和双子载波复用系统进行仿真研究。仿真结果表明，在20%的FEC阈值条件下，均匀（H=4）双子载波和PS（H=3.6，H=3.7，H=3.8）双子载波PDM-16QAM系统的传输距离相比均匀（H=4）单载波PDM-16QAM系统分别提升了2.3% （405 km）、21% （3698 km）、19.7% （3468 km）和14.5% （2549 km）。随后，搭建光纤环路传输实验平台，进一步验证所提方案的可行性。实验结果表明，在20% 的FEC阈值条件下，均匀双子载波和PS（H=3.8）双子载波PDM-16QAM系统的传输距离相比均匀单载波PDM-16QAM系统分别提升了5.6% （282 km）和46.2% （2323 km）。仿真与实验结果表明，在跨洋光纤通信系统中引入PS与SCM可有效提升系统的传输性能。
光通信 概率整形 子载波复用 非线性效应 跨洋光纤通信 光学学报
2022, 42(20): 2006001
1 西南交通大学信息光子与通信研究中心，四川 成都 611756
2 长飞光纤光缆股份有限公司光纤光缆制备技术国家重点实验室，湖北 武汉 430070
3 武汉光迅科技股份有限公司，湖北 武汉 430205
4 鹏城实验室，广东 深圳 518000
近年来网络数据流量呈现爆发式增长，光纤通信系统作为全球宽带网络的基础，已承载着90%以上的数据流量，并继续朝着多维、超大容量、超长距离等方向发展。搭建了一套模拟跨洋传输的超高容量距离积单模光纤传输系统实验平台。在发射端，根据传输信道光信噪比，采用不同信息熵产生不同传输速率的偏振复用概率整形16阶正交幅度调制光信号。光纤传输链路是由国产超低损大有效面积光纤与国产超宽带低噪声C波段掺铒光纤放大器组成。整个系统基于129个波长信道（波长范围为1529.8~1568.2 nm）进行了传输验证，得到的传输容量为28.09 Tbit/s，传输距离为12000 km，总容量距离积达到337 Pbit·s-1·km。
光通信 高速光纤通信 跨洋传输系统 波分复用 偏振复用 概率整形调制格式 光学学报
2022, 42(17): 1706003
School of Information Science & Technology, Center for Information Photonics & Communications, Southwest Jiaotong University, Chengdu 610031, Sichuan , China
Exploiting microwave photonic (MWP) techniques to generate and distribute high-frequency millimeter-wave (mm-wave) signals, termed mm-wave radio over fiber (m-RoF) signals, holds considerable potential for achieving high-density and high-capacity fifth-generation and beyond networks. Herein, we experimentally validate a broadband m-RoF uplink fronthaul transmission system using the MWP downconversion concept, which comprises receiving and processing radio-frequency (RF) signals in the unlicensed V-band at around 60 GHz. The proposed system harnesses the simple cascaded modulator topology, in which an ultrawideband off-the-shelf Mach–Zehnder modulator (MZM) renders a simple-structured remote radio head by directly encoding the broadband 60 GHz uplink RF signal into the optical carrier. The nonlinear transfer function of another MZM at the center unit is explored to achieve subharmonic downconversion using cost-effective low-frequency local oscillator signals. Based on proof-of-concept experiments, mm-wave four quadrature amplitude modulation orthogonal frequency-division multiplexing signals centered at frequencies ranging from 51 GHz to 70 GHz are successfully downconverted into signals at the intermediate frequency (IF) of 1.4 GHz. In the case of 1.2 m mm-wave, free-space, and 5 km m-RoF transmissions, the obtained IF signals with a total bandwidth of 2.4 GHz achieve a bit-to-error ratio performance lower than the 7% hard-decision forward error correction limit of 3.8 × 10-3. A gross bit rate of 10 Gbit/s can be achieved over a total spectrum of up to 10 GHz, which fully covers the globally unlicensed V-band of 57-66 GHz.
激光与光电子学进展
2022, 59(13): 1336002
Author Affiliations
Abstract
1 Center for Information Photonics and Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 611756, China
2 International Cooperation Research Center of China: Communications & Sensor Networks for Modern Transportation, Chengdu 611756, China
This erratum corrects a clerical error in the original manuscript [
Photon. Res.9, 1124 (2021)PRHEIZ2327-912510.1364/PRJ.419605].
Photonics Research
2022, 10(2): 02000415
红外与激光工程
2021, 50(7): 20211048
Author Affiliations
Abstract
1 Center for Information Photonics and Communications, School of Information Science and Technology, Southwest Jiaotong University, Chengdu 611756, China
2 International Cooperation Research Center of China: Communications & Sensor Networks for Modern Transportation, Chengdu 611756, China
Covert wireless communications are unprecedentedly vital for security and privacy of individuals, government, and military bodies. Besides encryption, hiding signal transmission deeply under noise background highly proliferates the covertness in the physical layer. A deep signal hiding leads to a low interception probability at the interceptor but a poor data recovery at the receiver. To ensure both high covertness and high-fidelity recovery, massive and dense optical comb channels are utilized for deep denoising through the analog spectrum convolution. Using an external modulation-based optical frequency comb (OFC) and a single detection branch, the available optical comb channels can sustainably scale up by breaking or greatly mitigating physical bottlenecks on immense hardware and spectrum requirements. Thus, a striking signal-to-noise ratio (SNR) rise can be achieved for deep denoising. Combination of 1024 comb channels (the first parallel comb channel number beyond 1000) and the analog spectrum convolution enable a record SNR enhancement of 29 dB for a microwave signal with a 10.24 GHz bandwidth and a 10 Mbit/s data rate, which is deeply hidden below the in-band noises by 18 dB or even 30 dB in both the frequency and time domains. This method opens a new avenue for covert communications.
Photonics Research
2021, 9(6): 06001124
西南交通大学信息光子与通信研究中心, 四川 成都 611756
在格雷编码布里渊光时域分析(BOTDA)传感器中,采用随机扰偏技术,不仅会在消除强偏振牵引效应时引起传感信号信噪比恶化,同时也会引入较强的偏振随机噪声(PRN)而降低传感信号的测量准确度。通过仿真分析和实验研究,证实了偏振随机噪声对传感信号的影响,并基于布里渊相移谱抑制了偏振随机噪声,实验结果表明该方法可使传感准确度提高3倍。
光通信 分布式光纤传感 布里渊光时域分析
